In the old days, transportation engineers and planners had a saying: "Paint it black." It referred to building new asphalt roads and parking lots, which occurred frequently in Bellevue's past.
But times have changed. Green is the new black, less means more and recycled beats new. From low-tech drainage techniques to high-tech street lights, incorporating elements of environmental sustainability into Bellevue transportation projects is now part of the conversation at City Hall.
The trend in the Transportation Department also fits into a wider effort toward sustainability, as outlined in Bellevue's Environmental Stewardship Initiative.
The initiative aims to integrate the natural and developed environments to create a sustainable urban habitat with clean air and water, habitat for fish and wildlife, and comfortable and secure places for people to live and work.
Transportation Director Goran Sparrman noted that Bellevue’s streets and sidewalks, made of asphalt and concrete, cover 14.5 percent of the city's total area of 32 square miles -- a significant amount of pavement.
"We have a better understanding today about the environmental consequences of our work -- which is to move people and freight efficiently around the city -- and about how we can minimize impacts," Sparrman said. "Several projects we've undertaken recently are attempts to incorporate that knowledge in Bellevue's transportation system."
Transportation-related projects that contain elements of environmental sustainability include:
Recycling materials in place: It's standard practice now to haul away broken up asphalt or concrete from road projects and recycle it for use on a different job. But last summer, Bellevue took that approach one step further on a major road widening project at Northup Way and 124th Avenue Northeast.
There, crews not only removed the old roadway, they used a special machine to pulverize the asphalt chunks in place and re-use the material immediately as a base for the new street. It not only saved numerous truck trips to remove the debris to an off-site recycler, it saved more than $20,000 in project costs.
Electric vehicle charging stations: Mass-produced electric cars are on the way, with some possibly going on sale in the Seattle area by the end of this year. At City Hall, work is under way to figure out how to encourage the creation of charging stations, so drivers of electric cars can find juice for their batteries. One way is to simply make sure that city staff have the knowledge and expertise to issue permits to people who want to install charging systems in their home garages.
Pervious sidewalks: Last May, the city installed its first section of "pervious concrete" sidewalk as part of a pilot project to test its strength and its ability to reduce storm water runoff. The 675-foot stretch of pervious sidewalk is located on the north side of Northup Way, between 165th and 168th avenues Northeast. One advantage of pervious sidewalks is that they reduce the amount of runoff to the stormwater system, allowing water to soak through the concrete into the ground. They also use less space, since a separate detention area, catch basin or vault is not needed.
LED street lights: In another pilot project, the city last year installed 10 new light emitting diode (LED) street lights along 118th Avenue Southeast, south of Main Street. The new LEDs provide a more uniform light than the traditional high-pressure sodium lamps they replaced, and are significantly more energy-efficient. Such lights have the potential to cut energy costs by up to 40 percent, a potentially major savings in Bellevue where there are approximately 8,000 street lights that use close to $520,000 worth of electricity annually.
Rain gardens/natural drainage: The city's first rain gardens incorporated into a transportation project were created last summer on 154th Avenue Southeast near Southeast Eighth Street. Located inside a pair of curb extensions, they feature shallow depressions with plantings that help absorb and filter rain instead of allowing it to drain to the city's storm water system. Plants were chosen for their ability to tolerate all types of weather and to fit in with the surrounding neighborhood. They include dwarf red-twig dogwood, beach strawberry, tufted hair grass, Oregon iris and peach blossom.
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